Development of magnetism-assisted in-tube solid phase microextraction of phenolic acids in fruit juices prior to high-performance liquid chromatography quantification.

Magnetism-assisted in-tube solid phase microextraction based on porous monolith mingled with Fe O nanoparticles was developed for capture of phenolic acids in fruit juices. First, poly (1-allyl-3-methylimidazolium bis [(trifluoro methyl) sulfonyl] imide-co-ethylene dimethacrylate) monolith embedded with Fe O nanoparticles was facile fabrication in a capillary and employed as microextraction column. Subsequently, a magnetic coil adopted to produce variable magnetic fields during extraction stage was twined on the microextraction column. The analytes contents in eluant were quantified by high performance liquid chromatogram with diode array detector. Various parameters affecting the extraction performance were inspected and optimized in detail. Results revealed that the exertion of magnetic fields in adsorption and desorption steps enhanced the extraction efficiencies of analytes from 44.9-64.0% to 78.6-87.1%. Under the optimal extraction factors, the limits of detection were between 0.012 and 0.061 μg/L, relative standard deviations for precision in terms of intra- and inter-day assay variability ranged from 1.9 to 9.8%. The introduced approach was successfully applied to simultaneously quantify the contents of five analytes in real fruit juices with satisfying fortified recoveries (80.1-116%). The obtained results well demonstrate the promising potential of the developed method in the highly sensitive quantification of trace phenolic acids in complex samples.